Police and swat team members respond to a call of a shooting at the Azana Spa in Brookfield, Wis. Sunday, Oct. 21, 2012. Multiple people were wounded when someone opened fire at the spa near the Brookfield Square Mall. Deputies are still looking for the gunman.

The gunman, who police had identified as Radcliffe Franklin Haughton, 45, is still at large and police are asking for the public's help in tracking him down.

Police said Haughton may be wearing a grey sweater, blue jeans, carrying a white and black backpack, and driving a black 2003 Mazda.

After the shooting, police said an improvised explosive device was found at the spa, but they did not indicate whether the suspect ever tried to set the device off.

The shooting occurred about 11 a.m. Sunday at the Azana Day Spa, a two-story, 9,000-square-foot building across the street from the Brookfield Square Mall in a middle- to upper-class community west of Milwaukee.

Haughton's father, Radcliffe Haughton Sr., who lives in Florida, told CBS News that the alleged shooter's wife is Zina Haughton, and she works at Azana.

Haughton Sr. said he knew they were having problems and that Zina had taken a restraining order out against him last week in court.

Milwaukee FBI spokesman Leonard Peace said its SWAT team, hostage negotiators and others were helping with the response. But he declined to say how many FBI personnel were involved in all or provide details on what had happened.

Robert Schmidt, spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said it had 10 agents participating.

It was the second mass shooting in Wisconsin this year. Wade Michael Page, a 40-year-old Army veteran and white supremacist, killed six people and injured three others before fatally shooting himself Aug. 5 at a Sikh temple south of Milwaukee.

The shooting at the mall took place less than a mile from where seven people were killed and four wounded on March 12, 2005, when a gunman opened fire at a Living Church of God service held at a hotel.